Merge pull request #81 from git-marijus/master

make home link on remote sites work again
use (numeric) abook_id for friends/followers in Twitter API. Many existing clients won't be able to handle xchans. Save those for the Red specific API.
Merge https://github.com/friendica/red into zpull
validate input to import_xchan(), as we don't consistently check it prior to entering this function
start using profile_flags in photo queries so we can start creating PHOTO_THING's
fix default channel setting after import
fix registration email (sitename)
Clone syncronisation might work better if we sent out the right kind of packet. We need to send them as 'notify' packets and arrange for pickup just like other authenticated message types.